This entity lost much of its membership after one 
This entity lost much of its membership after one of its leaders, David Stephenson, was convicted of murder. Four members of this organization bombed the 16th Street Baptist Church in the 1970's. First led by Nathan Bedford Forrest, this organization was romanticized in D.W. Griffith's Birth of a Nation. For 10 points, name this organization led by a Grand Wizard, whose white-hooded members terrorized blacks during Reconstruction.
This entity lost much of its membership after one of its leaders, David Stephenson, was convicted of murder.
{Ku Klux Klan} [or {KKK}]